Abstract
A trithiocarbonate with carboxyl group was synthesized and used as a chain transfer agent to control the reversible addition–fragmentation chain transfer (RAFT) homopolymerization and copolymerization in emulsion. The structure of chain transfer agent was characterized by nuclear magnetic resonance and Fourier transform infrared spectrometer. The molecular weights and polydispersity indexes (PDI) of polymers were analyzed by gel permeation chromatographer. The homopolymerization kinetics with different concentrations of the RAFT agent were investigated in detail and the theoretical molecular weights M n, th, chain transfer constant C tr, propagation rate constant k p, half reaction time of monomer t 1/2 and polymerization rate constant k were all calculated. These kinetic data indicated that the emulsion homopolymerization exhibits the characteristics of a “controlled/living” free radical polymerization. Meanwhile, the morphologies of polymer particles were analyzed by transmission electron microscope and the images revealed that the chain transfer agent concentration has influence on their particle sizes and distributions. The copolymerization kinetics of methyl methacrylate/butyl acrylate (MMA/BA) with different monomer compositions was also briefly studied. The experimental results showed the copolymerization kinetics was prominently affected by monomer compositions. The chain transfer ability of this RAFT agent to BA was lower and resulted in uncontrolled of molecular weights and wide PDI of P(MMA-co-BA) polymers.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call